// // detail/resolve_op.hpp // ~~~~~~~~~~~~~~~~~~~~~ // // Copyright (c) 2003-2010 Christopher M. Kohlhoff (chris at kohlhoff dot com) // // Distributed under the Boost Software License, Version 1.0. (See accompanying // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) // #ifndef BOOST_ASIO_DETAIL_RESOLVE_OP_HPP #define BOOST_ASIO_DETAIL_RESOLVE_OP_HPP #if defined(_MSC_VER) && (_MSC_VER >= 1200) # pragma once #endif // defined(_MSC_VER) && (_MSC_VER >= 1200) #include <boost/asio/detail/config.hpp> #include <boost/utility/addressof.hpp> #include <boost/asio/error.hpp> #include <boost/asio/io_service.hpp> #include <boost/asio/ip/basic_resolver_iterator.hpp> #include <boost/asio/ip/basic_resolver_query.hpp> #include <boost/asio/detail/bind_handler.hpp> #include <boost/asio/detail/fenced_block.hpp> #include <boost/asio/detail/handler_alloc_helpers.hpp> #include <boost/asio/detail/handler_invoke_helpers.hpp> #include <boost/asio/detail/operation.hpp> #include <boost/asio/detail/socket_ops.hpp> #include <boost/asio/detail/push_options.hpp> namespace boost { namespace asio { namespace detail { template <typename Protocol, typename Handler> class resolve_op : public operation { public: BOOST_ASIO_DEFINE_HANDLER_PTR(resolve_op); typedef boost::asio::ip::basic_resolver_query<Protocol> query_type; typedef boost::asio::ip::basic_resolver_iterator<Protocol> iterator_type; resolve_op(socket_ops::weak_cancel_token_type cancel_token, const query_type& query, io_service_impl& ios, Handler handler) : operation(&resolve_op::do_complete), cancel_token_(cancel_token), query_(query), io_service_impl_(ios), handler_(handler), addrinfo_(0) { } ~resolve_op() { if (addrinfo_) socket_ops::freeaddrinfo(addrinfo_); } static void do_complete(io_service_impl* owner, operation* base, boost::system::error_code /*ec*/, std::size_t /*bytes_transferred*/) { // Take ownership of the operation object. resolve_op* o(static_cast<resolve_op*>(base)); ptr p = { boost::addressof(o->handler_), o, o }; if (owner && owner != &o->io_service_impl_) { // The operation is being run on the worker io_service. Time to perform // the resolver operation. // Perform the blocking host resolution operation. socket_ops::background_getaddrinfo(o->cancel_token_, o->query_.host_name().c_str(), o->query_.service_name().c_str(), o->query_.hints(), &o->addrinfo_, o->ec_); // Pass operation back to main io_service for completion. o->io_service_impl_.post_deferred_completion(o); p.v = p.p = 0; } else { // The operation has been returned to the main io_service. The completion // handler is ready to be delivered. // Make a copy of the handler so that the memory can be deallocated // before the upcall is made. Even if we're not about to make an upcall, // a sub-object of the handler may be the true owner of the memory // associated with the handler. Consequently, a local copy of the handler // is required to ensure that any owning sub-object remains valid until // after we have deallocated the memory here. detail::binder2<Handler, boost::system::error_code, iterator_type> handler(o->handler_, o->ec_, iterator_type()); p.h = boost::addressof(handler.handler_); if (o->addrinfo_) { handler.arg2_ = iterator_type::create(o->addrinfo_, o->query_.host_name(), o->query_.service_name()); } p.reset(); if (owner) { boost::asio::detail::fenced_block b; boost_asio_handler_invoke_helpers::invoke(handler, handler.handler_); } } } private: socket_ops::weak_cancel_token_type cancel_token_; query_type query_; io_service_impl& io_service_impl_; Handler handler_; boost::system::error_code ec_; boost::asio::detail::addrinfo_type* addrinfo_; }; } // namespace detail } // namespace asio } // namespace boost #include <boost/asio/detail/pop_options.hpp> #endif // BOOST_ASIO_DETAIL_RESOLVE_OP_HPP